Non-transposing mute

ABSTRACT

A non-transposing mute having a metallic hemispherical resonator with a hollow acoustic filter attached thereto is provided for detachably fitting upon the rim of a brass musical instrument. A variety of tonal quality is available by choice of the particular filter selected by the musician.

llnited States Patent Gessick et al.

NON-TRANSPOSING MUTE Inventors: Benjamin R. Gossick; Karl A.

Schneider, both of Lexington, Ky.

The University of Kentucky Research Foundation, Lexington, Ky.

Filed: Sept. 6, 1972 Appl. No.: 286,666

Assignee:

U.S. Cl. 84/400 lint. Cl. GlOd 9/06 Field of Search 84/400, 387

References Cited UNITED STATES PATENTS 6/1919 Kidder 7/1925Schluesselburg 84/400 [451 Sept. 25, 1973 1,697,707 1/1929 Berg 84/4001,855,423 4/1932 Sansone 84/400 FOREIGN PATENTS OR APPLICATIONS 288,4354/1928 Great Britain 84/400 Primary Examiner-Richard B. WilkinsonAssistant Examiner-John F. Gonzales Att0meyWilliam E. Sherwood [57]ABSTRACT A non-transposing mute having a metallic hemisphericalresonator with a hollow acoustic filter attached thereto is provided fordetachably fitting upon the rim of a brass musical instrument. A varietyof tonal quality is available by choice of the particular filterselected by the musician.

5 Claims, 8 Drawing Figures NON-TRANSPOSING MUTE BACKGROUND OF THEINVENTION.

The use of acoustic attenuators, such as mutes, employed with brassmusical instruments has long been known, and many forms of the same havebeen proposed. Often such devices include acoustic absorbing or dampingmaterials serving essentially to muffle or reduce the intensity of soundat the expense of the tonal quality. It has now been discovered,however, that if a properly designed Helmholtz resonator is provided bythe mute (when attached to the rim of the bell of the instrument andhaving an acoustic filter associated therewith) no disturbing of thepitch of the sound will occur, no sound damping material is required inthe mute construction, and depending upon the structure of the acousticfilter the spectrum of sound emitted may be widely varied to suit theartistic range of expression of the musician.

In general, the sustained tone within a musical wind instrument, such asa comet, is developed by the establishing of standing waves within thepipe through the coherence of the periodic pulses produced at themouthpiece coinciding with pulses reflected from the outer end of theinstrument. A pressure wave, of course, will be reflected in a pipehaving an open end with the phase reversed, whereas with the end closed,the wave will be reflected in the same phase.

In accordance with the present invention a hemispherical Helmholtzresonator of sufficient size with,

for example, an iris aperture therein serves to close the bell of theinstrument and the incident wave is then reflected in phasesubstantially the same as if the bell were open. Accordingly, with thepresent type of nontransposing mute the effect on the pitch of thevarious notes of the instrument is substantially negligible, but thesound output is greatly suppressed. The only sound emitted is thatwhichescapes through the small iris aperture together with that which iscarried away by the vibrations of the walls of the instrument.Furthermore, the hollow acoustic filter device attached to the resonatorin communication with the iris aperture forms a passive acousticalnetwork, while the active acoustical network or tone generator, ismeanwhile confined to the bell which is being terminated in theresonator.

One feature of this construction embodies a decoupling action whichseparates the active brass instrument from the passive acoustic filter.This function is accomplished by providing sufficient acousticimpedance, as by employment of the small iris aperture. Thus thespectrum of sound emitted through the iris can be varied merely bychanging the filter device, and with assurance that such device will notinteract upon the tone generator itself or disturb its pitch.

SUMMARY OF THE INVENTION The invention employs a Helmholtz resonatormember of metallic material of generally hemispherical shape with meansat its periphery for attachment to the rim of the bell of the musicalinstrument and with a ferrule projecting outwardly from the resonatoralong the axis of the same. A hollow acoustic filter is detachablysecured to the ferrule and has an iris aperture smaller than thediameter of the ferrule. Fastening members spaced along the periphery ofthe resonator serve to detachably secure the mute to the rim of theinstrument.

Among the objects of the invention are the provision of an improvednon-transposing mute which permits a greater variety of tone quality andwhich extends the artistic range of expression of the musician; theprovision of a mute in which the tones are distinct and uniform inquality and in which rapid passages are not blurred; the provision of amute in which the feel of the instrument to the lips of the musician issubstan tially similar to the feel of an un-muted instrument; and theprovision of a mute requiring substantially no acoustical soundabsorbing material in its construction.

These and other objects and advantages of the invention will become moreapparent as the description proceeds and when considered in conjunctionwith the accompanying drawing in which FIG. l is a perspective view ofthe mute attached to the wind instrument.

FIG. 2 is an elevation view to a larger scale showing the exterior ofthe mute with the acoustic filter removed.

FIG. 3 is an elevation view similar to FIG. 2 showing the interior ofthe mute.

FIG. 4 is a sectional view taken on line 44 of FIG. 3.

FIG. 5 is a sectional view taken on line 55 of FIG. 2.

FIG. 6 is a longitudinal sectional view to a larger scale showing oneform of filter adapted for attachment at the ferrule shown in FIG. 5.

FIG. 7 is a longitudinal sectional view of a second form of filter; and

FIG. 8 is a longitudinal sectional view of a third form of filter.

Referring now to FIG. 1, the bell portion 10 ofa brass musicalinstrument, here shown as a comet, includes a rim llll over which themute is adapted to slip and to be detachably secured by fastening l2, l3and 14 later to be described. A substantially hemispherical member 15 isprovided with an axially aligned ferrule 16 or boss on its convexsurface and which ferrule has an aperture 17 therein of relatively smallsize as compared to the diameter of said member. The member serves asthe resonator and is of metallic material, preferably brass. At itsperiphery the member terminates in an outwardly extending planar flange18 to which is secured, as by spot welding, an annular metallicsupporting ring 19. Fasteners 20, 21 vand 22 project radially from thering and on the outer surface of the ring a suitable gasket 23 of softmaterial, such as felt, is secured.

The inner diameter of the ferrule is relatively small and, as anexample, a diameter of five-eighths inch when used with a resonatormember 15 having a diameter of 4 inches has proven to be satisfactory.Conveniently, the ferrule may be interiorly threaded and projects asuitabledistance outwardly of the member 15 to give a secure attachmentto the chosen acoustic filter now to be described.

One variety of filter is seen in FIG. 6 and comprises a metallic articlehaving a knurled rim portion 30 with a longitudinally extending shank 31threaded for engagement within the threaded ferrule. Significantly, anaxial passage 32, therein called the iris aperture, extends through thefilter and is flared at each end. The diameter of this aperture is thussmaller than the diameter of the ferrule and, for the example given, maybe about one-eighth inch. The inner end of the shank is a formed with acavity 33 whose curvature may approximate the curvature of the resonatormember so that when the filter is fully inserted the desired wavereflection within the mute is improved.

' A second form of filter is shown in FIG. 7 and comprises a similar rimportion 40, shank 41 and iris aperture 42. However, in order to secure adifferent tonal quality the diameter of the aperture is increased, forexample, to about one-fourth inch, the curvature 43 of the cavity ischanged, and a hollow stem 44 is added.

A third form of filter is illustrated in FIG. 8 and comprises a rimportion 50, shank 51, and iris aperture 52, for example about one-eighthinch in diameter. However, in order to secure still another tonalquality the curvature 53 is different, the length of the hollow stem 54is longer than in FIG. 7 and terminates in a flared opening smaller indiameter than the corresponding flared opening of stem 44. Other designsof the passive acoustical filter may be employed without departing fromthe invention but in each form the pitch of the instrument is notchanged.

Passing now to FIGS. 3 and 4, after the musician selects the particularfilter which he intends to use and has attached it to the resonator ofthe mute he will wish to attach the assembled mute quickly and easily tothe bell of the instrument. One arrangement to serve this purposecomprises a pair of fasteners and 21 each of which includes a plasticblock 60 rigidly secured as by a screw 61 to an ear 62 projectingradially from the supporting ring 19. The lower side of the block isbevelled to provide a space into which the rim ll of the brassinstrument bell is slipped when the mute is installed, and the feltgasket 23 is then compressed by the rim of that bell. It is to be notedthat the gasket is entirely out of the resonator space and does notconstitute acoustical absorbing material. However, if the aperture 17were completely stopped with a plug the gasket would have a limitedsound absorbing action.

By contrast with the described fastenings 20 and 21 the fastening 22(FIG. 3) includes a longer block 63 pivoted as by means of a bolt 64, toa longer ear of the ring 19 and which may be swung into and out ofengagement with the lower portion of the rim ll of the instrumentfollowing the attachment of the fasteners 20 and 21 to that rim. Othermeans for detachably joining the mute to the instrument may, of course,be employed, as for example spring-loaded fasteners, or cam fasteners inwhich the mute is rotated into and out of fastened position.

Having thus described preferred forms of coordinated parts of theimproved mute by means of which the invention may be practiced, it willbe understood that the invention may be embodied in other forms withoutdeparting from the scope defined by the appended claims.

What is claimed is:

1. A non-transposing mute for a brass musical instrument having a bellportion comprising, a generally hemispherical metallic member includinga relatively small ferrule at its axis and projecting outwardlytherefrom, means for detachably securing the periphery of said memberclosely adjacent the rim of the bell portion and with said memberpositioned outwardly of the bell portion, and a hollow acoustic filterdetachably secured to said ferrule and projecting outwardly therefrom,said filter serving to communicate the interior of said member with theambient air and having a decoupling aperture therein smaller than theinner diameter of said ferrule.

2. A mute as defined in claim 1 wherein said filter includes a concavesurface facing into said resonator member and leading to the entrance ofsaid decoupling aperture.

3. A mute as defined in claim 1 substantially devoid of acousticalabsorbing materials.

4. A mute as defined in claim 1 including a planar flange on saidmember, said flange providing a support for said securing means.

5. A mute as defined in claim 4 including a compressible gasket incontact with the rim of the bell portion and interposed between saidflange and the bell portion when the mute is mounted on the instrument.

1. A non-transposing mute for a brass musical instrument having a bellportion comprising, a generally hemispherical metallic member includinga relatively small ferrule at its axis and projecting outwardlytherefrom, means for detachably securing the periphery of said memberclosely adjacent the rim of the bell portion and with said memberpositioned outwardly of the bell portion, and a hollow acoustic filterdetachably secured to said ferrule and projecting outwardly therefrom,said filter serving to communicate the interior of said member with theambient air and having a decoupling aperture therein smaller than theinner diameter of said ferrule.
 2. A mute as defined in claim 1 whereinsaid filter includes a concave surface facing into said resonator memberand leading to the entrance of said decoupling aperture.
 3. A mute asdefined in claim 1 substantially devoid of acoustical absorbingmaterials.
 4. A mute as defined in claim 1 including a planar flange onsaid member, said flange providing a support for said securing means. 5.A mute as defined in claim 4 including a compressible gasket in contactwith the rim of the bell portion and interposed between said flange andthe bell portion when the mute is mounted on the instrument.